Head protecting airbag device

ABSTRACT

In a head protecting airbag device, an airbag includes an inflation portion and a connection port portion. The connection port portion includes: an outlet side portion having a communication port to the inflation portion at its lower end; and an inlet side portion for inserting an inflator therein. The inflator includes a body portion having a gas discharge port, and a diffuser having a gas outlet port. The diffuser is connected with the body portion so as to cover the gas discharge port, having its two ends forced into contact with the outer circumference of the body portion. The inflator is connected to a connection port portion with good sealing properties and the gas outlet port faces toward the communication port of the connection port portion and thus toward the inflation portion. This head protecting airbag device simplifies the connection structure between the inflator and the airbag while retaining the quick expansion and inflation of the airbag.

This application is a divisional application of U.S. patent applicationSer. No. 10/299,656 filed Nov. 20, 2002 is now U.S. Pat. No. 6,860,506,which claims priority from Japanese patent application of Ogata et al.,filed Nov. 22, 2001, No. 2001-358093, the complete disclosure of whichis hereby incorporated into the present application by this reference.

This application claims priority from Japanese patent application ofOgata et al, filed Nov. 22, 2001, No. 2001-358093, the completedisclosure of which is hereby incorporated into the present applicationby this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a head protecting airbag device. Theairbag of the head protecting airbag device is folded and housed in theupper peripheral edge of a window in the interior side of a vehicle sothat it may be expanded and inflated, when it admits an inflating gas,to cover the interior side of the window.

2. Description of the Related Art

Usually in the head protecting airbag device of this kind, an inflatedairbag protects an occupant. Therefore, the head protecting airbagdevice is desired, when activated, to develop the airbag quickly. Theconstruction of Unexamined Published Japanese Patent Application No.2000-296753 is known as the head protecting airbag device which isconstructed to expand the airbag quickly.

This head protecting airbag device is provided with two connection portportions at the upper edge side near the longitudinal middle of theairbag. These two connection port portions are opposed to each other inthe longitudinal direction. The front and rear ends of the inflator areindividually inserted into the two connection port portions so that theinflator is connected with the two connection port portions in astraight line.

When this airbag device is activated, the inflating gas is dischargedfrom the two ends of the inflator in the axial direction of theinflator. Then, the inflating gas flows, through the two connection portportions of the airbag, in two directions, i.e., to the front side andto the rear side in the longitudinal direction of the vehicle so as toinflate the airbag.

In the head protecting airbag device of the prior art, however, theinflating gas, as discharged from the two ends of one inflator, isguided into the airbag through the two connection port portions. Inother words, the airbag device of the prior art has two connectionportions which connect the inflator and the connection port portions ofthe airbag. Therefore, in the head protecting airbag device of the priorart, the connecting work becomes complicated in the light of sealingproperties, which caused a large number of working steps and a highcost.

Especially in the head protecting airbag device of the prior art, thefront and rear ends of the inflator are individually inserted into theconnection port portions. These connection port portions have to besealed up by forcing them to contact with the outer circumference of theinflator. However, the inflator and the two connection port portions areconnected in a straight line so that the inflating gas discharged in theaxial direction of the inflator flows in the axial directions of theindividual connection port portions. In other words, the connection portportions are easily pulled out from the end portions of the inflator ifa pressure put on the individual connection port portions against theouter circumference of the inflator is low. This makes it necessary toconnect the individual connection port portions and the inflator withgreat connection strength, including sealing properties. As a result,the head protecting airbag device of the prior art needs a large numberof working-steps and thus high cost for assembly.

SUMMARY OF THE INVENTION

The present invention is intended to solve the above-specified problems.Specifically, the invention has the objective of providing a headprotecting airbag device which simplifies the connection structurebetween an inflator and an airbag while retaining a quick expansion andinflation of the airbag and which reduces the number of working-stepsand the cost of its assembly.

A head protecting airbag device according to the present inventioncomprises an airbag and an inflator for feeding an inflating gas to theairbag. The airbag is folded and housed at the upper peripheral edge ofthe window along the longitudinal direction on the interior side of avehicle and is expanded and inflated downward when it admits aninflating gas to cover the interior side of the window. Moreover, theairbag includes an inflation portion and one cylindrical connection portportion. The inflation portion is inflated when it admits the inflatinggas to separate an interior side wall portion and an exterior side wallportion of the airbag, thereby to shield the window. The connection portportion is arranged at generally the middle in the vehicle longitudinaldirection of the upper edge of the airbag and is formed to communicatewith the inflation portion, protruding upward from the inflationportion. The connection port portion guides the inflating gas from theinflator to the inflation portion. The connection port portion includesan outlet side portion and an inlet side portion. The outlet sideportion has a generally vertical axial direction and has a communicationport at its lower end for communicating with the inflation portion, torelease the inflating gas to the inflation portion. The inlet sideportion is arranged above the outlet side portion and is connected tothe inflator for admitting the inflating gas from the inflator.Moreover, the inflator includes a body portion and a diffuser. The bodyportion is formed into a cylinder having a gas discharge port opened onthe outer circumference for discharging the inflating gas. The diffuseris formed of a metal into a cylindrical shape to cover the gas dischargeport of the body portion, and is attached to the body by pressing thetwo ends on the outer circumferential surface of the body. Moreover, thediffuser has a gas outlet port opened on its outer circumference forreleasing the inflating gas. The inflator is inserted into the inletside portion of the connection port portion of the airbag and isconnected to the connection port portion with good sealing. Thus, theinflator is arranged to have its gas outlet port opposed to thecommunication port of the connection port portion and to face toward theinflation portion.

Here, close to the longitudinal middle of the airbag where theconnection port portion is arranged is not limited to the longitudinalcenter of the airbag but means the position at which a part of theinflation portion is arranged on both the front side and the rear sideof the connection port portion.

In the head protecting airbag device according to the invention, whenactivated, the inflating gas discharged from the gas discharge port ofthe body portion of the inflator goes through the clearance between theouter circumference of the body portion and the inner circumference ofthe diffuser and flows into the single connection port portion of theairbag. Moreover, the inflating gas is released from the communicationport of the connection port portion into the inflation portion of theairbag. Then, the airbag inflates at its inflation portion by admittingthe inflating gas so that it is expanded downward from the upper edge ofthe window.

Specifically, in the head protecting airbag device of the presentinvention, the inflating gas from the inflator is fed to the inner sideof the airbag through the single connection port portion. Unlike theprior art in which the two ends of the inflator are connected to the twoconnection port portion, therefore, the airbag device of the inventionhas its connection with the inflator through a single connection portportion. Therefore, it is easy to connect the inflator and theconnection port portion.

When the inflating gas flows into the inflation portion of the airbag,on the other hand, the gas outlet port of the inflator is opposed to thecommunication port at the lower end of the connection port portion andface toward the inflation portion. The gas outlet port is opened on theouter circumference of the diffuser and is axially directed generallyperpendicular to the axial direction of the inflator. Specifically, thecommunication port in the outlet side portion of the connection portportion is axially directed generally perpendicular to the axialdirection of the inflator, as the gas outlet port. As a result, theinlet side portion of the connection port portion into which theinflator is inserted is roughly perpendicular to the axial direction ofthe communication port, that is, is bent generally perpendicular to theoutlet side portion of the connection port portion.

Therefore, the inflating gas from the inflator is injected generallyperpendicular to the axial direction of the body portion or the diffuserof the inflator so that it flows into the outlet side portion andfurther into the inflation portion of the airbag. At this time, even ifthe outlet side portion is given downward force by the injection forceof the inflating gas, the inner circumference of the inlet side portion,especially, the portion away from the communication port, is held by theportion of the outer circumference of the inflator away from thecommunication port, so that the outlet side portion is prevented fromseparating from the inflator. As a result, even if the connectionstructure between the inflator and the inlet side portion of theconnection port portion is simplified to weaken the connection strength,the inflator itself holds the connection port portion with a part of itsouter circumference, when the airbag device acts. Specifically, even ifthe connection structure between the inflator and the inlet side portionof the connection port portion is simplified, and thereby weakening theconnection strength, it is possible to prevent the connection portportion from separating from the inflator.

On the other hand, the assembly of the diffuser with the body portion ofthe inflator is made by the simple structure in which the two ends ofthe diffuser are pressed on the body portion. However, the inflating gasis injected generally perpendicular to the axis of the body portion orthe diffuser from the gas outlet port of the diffuser. Thus, even if theassembling force of the two ends of the diffuser to the body portion isweak, therefore, the diffuser is prevented from separating from the bodyportion. As a result, the inflator itself can be assembled by connectingthe diffuser and the body portion simply.

The inflating gas that flows into the inflation portion of the airbagnaturally flows toward the longitudinal middle position of the inflationportion through the connection port portion. Therefore, the inflatinggas promptly reaches the two longitudinal ends of the inflation portionso that the airbag device can retain quick expansion and inflation ofthe inflation portion of the airbag.

In the head protecting airbag device according to the invention,therefore, the quick expansion and inflation of the airbag is retainedwhile simplifying the connection structure between the inflator and theairbag. In the airbag device of the invention, moreover, the inflatoritself can be simply assembled and thereby the number of working-stepsand the cost of its assembly are reduced.

Moreover, the diffuser of the inflator are so assembled on the bodyportion as to force the two ends of the diffuser to contact with thebody portion. In short, the diffuser overlaps the body portion so thatthe inflator can be compactly constructed without elongating its axiallength.

Moreover, it is desired that two gas outlet ports are arranged in thediffuser for releasing the inflating gas in two directions obliquely,i.e., forward and downward, and rearward and downward. In thisconstruction, the inflating gas flows in the two directions, i.e.,forward and downward, and rearward and downward, into the inflationportion from the two gas outlet ports of the diffuser through thecommunication port of the outlet side portion. Therefore, the inflatinggas smoothly reaches the two longitudinal ends of the inflation portionso that the airbag can retain a quicker expansion and inflation.

Moreover, it is desired that the gas outlet port is arranged at the sideof the center or the end portion of the inflator on the side apart fromthe gas discharge port in case the gas discharge port is arranged closeto the end portion of the body portion. This construction enables theuse of an inflator in which the side of the gas discharge port of thebody portion cannot be inserted into the inlet side portion of theconnection port portion, such as an inflator of a stored gas type whichis charged with a cold gas. In a stored gas type inflator, specifically,the actvating lead wires are arranged at the end on the side where thegas discharge port of the body portion is arranged. An inflator of thiskind is inserted from the end portion thereof on which no lead wires arearranged into the inlet side portion of the connection port portion sothat the end to which the lead wires are connected may be exposed fromthe opening of the inlet side portion of the connection port portion.With the aforementioned construction, the gas outlet port of thediffuser is smoothly arranged to face the communication port.

Moreover, it is desired that the inlet side portion of the connectionport portion of the airbag is arranged along the longitudinal directionof the vehicle. With this construction, the inflator is inserted intothe inlet side portion while the inlet side portion of the connectionport portion of the airbag is arranged in the longitudinal direction ofthe vehicle, i.e., in parallel to the inflation portion of the airbag.Therefore, the inflator is easily arranged in the narrow space on theupper edge side of the windows of the vehicle.

Still moreover, the connection port portion of the airbag may have theinlet side portion bent from the outlet side portion, to have anL-shape.

Moreover, the inlet side portion is opened on both front and rear endsand is formed to protrude to the front and rear sides from the upperside of the outlet side portion. It is desired that the inlet sideportion is sealed on the inflator at two portions of the front and rearsides on either side of the outlet side portion, by being pressedagainst the outer circumference of the inflator along thecircumferential direction. With this construction, the outlet sideportion constitutes the vertical rod portion of the T-shape whereas theinlet side portion constitutes the horizontal rod portion of theT-shape, so that the connection port portion forms a T-shape. Moreover,the two sealed portions of the inlet side portion are formed at thefront and rear ends on either side of the outlet side portion, so thatthe inflator may be inserted from either side of the ends of the inletside portion. As a result, the flexibility of connecting the inflatorand the airbag is increased. Moreover, the sealed portions of the inletside portion on the inflator are individually formed by being pressedagainst the outer circumference of the inflator along thecircumferential direction, although they are formed at two positions offront and rear sides on either side of the outlet side portion.Specifically, the sealed portions retain the sealing pressure in thecircumferential direction or in the direction generally perpendicular tothe injection direction of the inflating gas which is injected from thegas outlet port of the diffuser. Therefore, the sealed portions of theinlet side portion retain the sufficient sealing properties even if thesealing pressure is not high. As a result, the sealing structure of theinlet side portion and the inflator is simplified, maintaining goodworkability in connecting the inflator and the connection port portion.

Moreover, it is desired that the inflator is attached to the vehicularbody at two positions of the front and rear sides on either side of theoutlet side portion. With this construction, the inflator itself isstably mounted on the vehicular body. When the inflator is activated,moreover, pressure is applied to the outlet side portion in thedirection away from the inflator by the injection force of the inflatinggas. However, the inflator is inserted into the inlet side portion whichis protruded to the front and rear above the outlet side portion.Therefore, the inflator itself restricts the movement of the outlet sideportion at its two ends of the inlet side portion on either side of theoutlet side portion, thereby to support the connection port portionstably.

Moreover, it is desired that the sealed portion of the diffuser has aclearance from the outer circumference of the body portion, in case theinlet side portion is sealed on the outer circumference of the inflatorat least at one position by being pressed against the circumference ofthe diffuser along the circumferential direction. With thisconstruction, even if the sealing pressure for sealing the inlet sideportion on the diffuser is raised to a predetermined or higher level,the diffuser can be warped to narrow the clearance from the bodyportion. Therefore, the sealing pressure on the inlet side portion neednot be strictly set, which facilitates the connecting work of theconnection port portion and the diffuser.

Moreover, the gas outlet port of the diffuser may be arranged to projectinto the outlet side portion closer to the inflation portion. With thisconstruction, the inflating gas flows smoothly into the inflationportion.

Moreover, it is desired that the inflation portion of the airbagincludes a feed passage portion and a shielding body portion. The feedpassage portion is arranged on the upper edge side of the airbag tocommunicate with the connection port portion, and extends in thelongitudinal direction of the vehicle. The shielding body portion isarranged below the feed passage portion, and substantially covers theinterior side of the window when inflated. Moreover, the shielding bodyportion includes a plurality of vertical cells lined up in thelongitudinal direction of the vehicle so as to inflate into vertical rodshapes with the inflating gas introduced through the feed passageportion into the inflation portion. With this construction, theinflating gas flowing into the airbag flows into the feed passageportion which is arranged in the longitudinal direction of the vehicleon the upper edge of the airbag. Therefore, the vertical cells on thefront and rear ends of the inflation portion are smoothly inflated sothat the airbag attains quick expansion and inflation.

In this case, the airbag may also be constructed in the followingmanner. The inflation portion of the airbag includes a communicationpassage portion arranged along the longitudinal direction of the vehicleon the lower edge side of the airbag for providing communicationsbetween the individual vertical cells and the lower end. One of thevertical cells is arranged right below the connection port portion inthe airbag with its opening narrowed on the side of the feed passageportion. The front and rear adjacent vertical cells thereof areindividually closed at their upper ends.

With this construction, the vertical cell just below the connection portportion has a narrowed opening on the side of the feed passage portion,and the two vertical cells on the two sides thereof are closed at theirupper ends. Therefore, the inflating gas flowing from the outlet sideportion of the connection port portion into the inflation portion isprevented from flowing in a large quantity into the vertical cells inthe vicinity of the connection port portion. In other words, theinflating gas flowing from the outlet side portion into the inflationportion is smoothly guided to the front and rear sides of the feedpassage portion. Further, a part of the inflating gas smoothly flowsfrom the vertical cell just below the connection port portion, through acommunication passage portion, into the vertical cells at the front andrear ends of the inflation portion. Therefore, the quick expansion andinflation of the airbag are more promoted.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front elevation showing the used state of a headprotecting airbag device according to a first embodiment of theinvention, as taken from the interior side of a vehicle;

FIG. 2 is a front elevation of an airbag to be used in the firstembodiment;

FIG. 3 is a partially enlarged section of the vicinity of an inflator inthe airbag device of the first embodiment;

FIG. 4 is a bottom view of an inflator to be used in the firstembodiment;

FIG. 5 is a partially enlarged section of the vicinity of a connectionport portion of an airbag in an airbag device according to a secondembodiment;

FIG. 6 is a partially enlarged section of the vicinity of an inflator inthe airbag device of the second embodiment;

FIG. 7 is a partially enlarged section of the vicinity of a connectionport portion of an airbag in an airbag device according to a thirdembodiment;

FIG. 8 is a partial front elevation of the vicinity of the connectionport portion of the airbag used in the third embodiment;

FIG. 9 is a partially enlarged section of the vicinity of a connectionport portion of an airbag in an airbag device according to a fourthembodiment;

FIG. 10 is a partial front elevation of the vicinity of the connectionport portion of the airbag used in the fourth embodiment; and

FIG. 11 is a partially enlarged section of the vicinity of an inflatorin an airbag device of a fifth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The invention will be described below by way of embodiments shown in thedrawings. In addition, the invention is not limited to the embodiments.All modifications within the requirements of the claims and equivalentswith respect to the requirements should be included in the scope of theclaims.

As shown in FIG. 1, a head protecting airbag device M1 according to oneembodiment of the invention includes an airbag 11. The airbag 11 foldedis housed in the lower edge of a front pillar portion FP, the lower edgeof a roof side rail portion RR and above a rear pillar portion RP in theupper peripheral edge of windows W (W1, W2 and W3) on the interior sideof a vehicle V. Here in the vehicle V of the embodiment, two first andsecond intermediate pillar portions P1 and P2 are arranged between thefront pillar FP and the rear pillar portion RP. The airbag 11 is housedto extend over those pillar portions P1 and P2.

The airbag device M1 is constructed to include the airbag 11, aninflator 36, mounting brackets 33 and 57, clamps 55 and an airbag cover8.

The airbag cover 8 is built, as shown in FIG. 1, of the lower edges 4 aand 5 a of a front pillar garnish 4 and a roof head lining 5. The frontpillar garnish 4 is arranged in the front pillar portion FP, and theroof head lining 5 is arranged in the roof side rail portion RR. Theairbag cover 8 is arranged to cover the interior side of the airbag 11folded and housed. Moreover, the cover 8 is constructed to open into theinterior of the vehicle by the push of the airbag 11 so that the airbag11 being expanded and inflated may protrude into the vehicularcompartment.

The airbag 11 is manufactured by hollow-weaving of polyamide yams or thelike. The housed airbag 11 is expanded and inflated downward from theupper edge side of the window W by admitting an inflating gas G from theinflator 36, as shown in FIGS. 1 to 3. Then, the airbag 11 havingcompleted its inflation covers the interior side of the windows WI, W2and W3 and the pillar garnishes 7 and 6 of the first and secondintermediate pillar portions P1 and P2 and the rear pillar portion RP.On the other hand, referring now to FIG. 2 the airbag 11 comprises a gasinlet portion 13 admitting the inflating gas G therein, and a blockingportion 25 which allows no inflating gas G to pass therein.

The gas inlet portion 13 is provided with an inflation portion 14 and aconnection port portion 19. The inflation portion 14 is inflated, whenthe inflating gas G flows in, to separate an interior side wall portion14 a and an exterior side wall portion 14 b. The inflation portion 14which has completed its inflation shields the windows W and covers theinterior sides of the pillar portions P1 and P2. The connection portportion 19 guides the inflating gas G from the inflator 36 into theinflation portion 14. The connection port portion 19 is formed in aT-shaped cylinder, as viewed from the interior compartment, and isarranged at generally the middle in the vehicular longitudinal directionat the upper edge 11 a of the airbag 11. The connection port portion 19communicates with the inflation portion 14 and is protruded upward fromthe inflation portion 14.

The inflation portion 14 includes a feed passage portion 15, a shieldingbody portion 16 and a communication passage portion 17. The feed passageportion 15 is arranged at the side of the upper edge 11 a of the airbag11 and in the longitudinal direction of the vehicle V. The shieldingbody portion 16 is arranged below the feed passage portion 15 andsubstantially covers the interior sides of the windows W and the pillarportions P1 and P2. The communication passage portion 17 is arranged onthe side of the lower edge 11 b of the airbag 11 and in the longitudinaldirection of the vehicle. In the shielding body portion 16, there arelongitudinally juxtaposed a plurality of vertical cells 16 a which bulgein vertical rod shapes. The feed passage portion 15 is formed to feedthe inflating gas G smoothly to the two front and rear ends of theinflation portion 14. The individual vertical cells 16 a communicate attheir upper end sides with the feed passage portion 15, excepting thevertical cells 16 aa and 16 ac adjoining the vertical cell 16 ab justbelow the connection port portion 19. Moreover, the individual verticalcells 16 a communicate at their lower ends with the communicationpassage portion 17. This communication passage portion 17 feeds theinflating gas G having reached the lower end of the vertical cell 16 ab,smoothly to the two front and rear sides of the inflation portion 14.

The connection port portion 19 includes an inlet side portion 20 and anoutlet side portion 21. The inlet side portion 20 is so connected to theinflator 36 as to admit the inflating gas G from the inflator 36. Theoutlet side portion 21 releases the inflating gas G to the inflationportion 14. The outlet side portion 21 is formed into a generallycylindrical shape having an axis generally in the vertical direction.The outlet side portion 21 is provided at its lower end with acommunication port 21 a, which communicates with the feed passageportion 15 of the inflation portion 14. The inlet side portion 20 isarranged above the outlet side portion 21. The inlet side portion 20 isformed into a generally cylindrical shape having an axis in thelongitudinal direction of the vehicle, and is provided with openings 20b and 20 d in its two front and rear end portions 20 a and 20 c. Theoutlet side portion 21 communicates at its upper end with thelongitudinal middle of the inlet side portion 20.

The blocking portion 25 is constructed by joining the interior side wallportion 14 a and the exterior side wall portion 14 b. In the case of theembodiment, the blocking portion 25 is constructed of mounting portions26, a peripheral edge portion 27, thickness regulating portions 28,connection portions 29 and board portions 30.

The peripheral edge portion 27 is arranged adjacent to the gas inletportion 13. The peripheral edge portions 27 are densely woven to causeno gas leakage. The mounting portions 26 are provided in plurality(e.g., nine in the embodiment) and are individually protruded upwardfrom the peripheral edge portion 27 at the upper edge 11 a and fromtriangular board portions 30 a of the airbag 11. To each mountingportion 26, there is fixed a mounting bracket 33 for attaching theairbag 11 to the body 1 of the vehicle V. Moreover, each mountingportion 26 is provided with a mounting hole 26 a through which to inserta mounting bolt 34. The individual mounting portions 26 are fixedtogether with the mounting brackets 33 on an inner panel 2 of sheetmetal on the side of the body 1 by using the mounting bolts 34.

The board portions 30 are arranged to maintain the entire shape of theairbag 11 and to reduce the volume of the gas inlet portion 13. Theboard portions 30 helps shorten the time period for the airbag 11 tostart and complete its inflation. Moreover, the board portions 30 arecomposed of the triangular board 30 a arranged on the front end side ofthe airbag 11, and a triangular board 30 b arranged on the rear end sideof the airbag 11. The thickness regulating portions 28 are so verticallyarranged as to divide the individual vertical cells 16 a. Here, thethickness regulating portion 28A on the front of the vertical cell 16 aais made to have a larger width than that of the remaining thicknessregulating portions 28.

The connection portions 29 close off the upper side of the verticalcells 16 aa and 16 ac by connecting the thickness regulating portions 28and 28 across the individual vertical cells 16 aa and 16 ac.

Moreover, the thickness regulating portions 28 and 28 located just belowthe connection port portion 19 and on the upper end side of the verticalcell 16 ab and opposed to each other, are provided with projections 28 afor narrowing the opening of the vertical cell 16 ab. These projections28 a prevent the inflating gas G flowing from the outlet side portion 21of the connection port portion 19 to the inflation portion 14, fromflowing in a large amount into the vertical cell 16 ab. Therefore, theinflating gas G flowing from the outlet side portion 21 into theinflation portion 14 is easily guided to the front and rear of the feedpassage portion 15 by those projections 28 a.

As shown in FIGS. 1, 3 and 4, the inflator 36 is constructed to includea body portion 37 and a diffuser 45. The body portion 37 is formed intoa cylinder and has gas discharge ports 42 opened on its outercircumference for discharging the inflating gas G. The diffuser 45 isformed of a metal into a generally cylindrical shape for covering thegas discharges ports 42 of the body portion 37. The diffuser 45 isconnected to the body portion 37 by forcing a root end of the diffuseronto a head portion of the body portion 37.

The body portion 37 is of the stored gas type, which is charged with acold gas. The body portion 37 is constructed of a generallycolumn-shaped base portion 38 arranged on the side of a rear end 37 b,and a generally column-shaped head portion 39 having a slightly smallerdiameter than the base portion 38 and arranged at the front end (orleading end) 37 a. The gas discharge ports 42 are arranged on the outercircumference closer to the leading end 39 a of the head portion 39.With the leading end face of the head portion 39, there is connected aconnector 52 for inputting an activation signal from the activationcircuit of the airbag device M1. Here, reference numeral 53 in FIG. 3designates a lead wire. On the side of a root portion 39 b of the headportion 39, on the other hand, there is arranged throughout thecircumference a groove 41 for mounting the diffuser 45. Throughout thecircumference of the leading end of the head portion 39, moreover, thereis formed an inward step 40 for mounting the diffuser 45.

The diffuser 45 is formed of a sheet metal into a generally cylindricalshape. The diffuser 45 is provided, on the side of its leading end (orfront end) 45 a, with a flange portion 46, which is protruded in theinner circumferential direction. The diffuser 45 is provided, on theside of its root portion (or rear end) 45 b, with a caulking portion (orplastically deformed portion) 47 to be fitted in the groove 41 of thebody portion 37. In front of the caulking portion 47, there is formed abottomed cylindrical bulge 48, which is protruded downward. The bulge 48is formed into a conical shape having two gas outlet ports 49 and 50opened in a circular shape. These gas outlet ports 49 and 50 release theinflating gas individually downward generally perpendicularly to theaxial direction of the body portion 37 of the inflator 36 and thediffuser 45. More specifically, the gas outlet port 49 releases theinflating gas G obliquely, forward and downward. When the airbag deviceis mounted on the vehicle, moreover, the inflating gas G, as releasedfrom the gas outlet port 49, is guided via the communication port 21 aof the outlet side portion 21 of the connection port portion 19 to thefront side of the feed passage portion 15 in the inflation portion 14 ofthe airbag 11. Moreover, the gas outlet port 50 releases the inflatinggas G obliquely, rearward and downward. When the airbag device ismounted on the vehicle, moreover, the inflating gas G released from thegas outlet port 50 is guided through the communication port 21 a of theoutlet side portion 21 of the connection port portion 19 to the rearside of the feed passage portion 15 in the inflation portion 14 of theairbag 11.

The diffuser 45 has an O-ring 44 arranged on the inner side face of theflange portion 46. When the diffuser 45 is assembled with the bodyportion 37, it is mounted from its root portion 45 b on the head portion39 of the body portion 37, and the flange portion 46 is brought incontact through the O-ring 44 to the step 40. If the caulking portion 47is fitted in the groove 41, the front and rear ends 45 a and 45 b areassembled with good sealing with the head portion 39 of the body portion37. As a result, the diffuser 45 is assembled with the body portion 37,so that the inflator 36 is assembled. Here, numeral 43 in FIG. 3designates a ring spacer of a synthetic resin, which is arranged on theouter circumference of the groove 41 so as to protect the groove 41 fromany damage.

When the inflator 36 assembled is connected to the connection portportion 19, the diffuser 45 is inserted into the inlet side portion 20in the connection port portion 19 of the airbag 11 with the gas outletports 49 and 50 being directed downward. Then, the front and rear endportions 20 a and 20 c of the inlet side portion 20 are held by theclamps 55 and pressed onto the outer circumferences of the front andrear ends 45 a and 45 b of the diffuser 45. Thus, the inflator 36 isconnected to the connection port portion 19. At this connecting time,the gas outlet ports 49 and 50 of the diffuser 45 face opposite thecommunication port 21 a from above, and are arranged to face toward thefeed passage portion 15 of the inflation portion 14.

The clamps 55 are formed of a sheet metal into an annular shape. And,these clamps 55 are plastically deformed partially into a smallerinternal diameter thereby to force the front and rear end portions 20 aand 20 c of the inlet side portion 20 in the connection port portion 19to contact with the entire outer circumference of the end portions 45 aand 45 b of the diffuser 45.

The mounting bracket 57 has a holding portion 57 a and a mountingportion 57 b. The holding portion 57 a sheathes and clamps the baseportion 38 of the body portion 37 of the inflator 36. The mountingportion 57 b is protruded from the holding portion 57 a. The mountingportion 57 b is provided with mounting holes 57 c and 57 c for insertingmounting bolts 58 therethrough. The individual mounting bolts 58 arefastened on the inner panel 2 on the side of the body 1 of the interiorside of the roof side rail portion RR. The mounting bracket 57 ismounted and fixed on the inner panel 2 on the side of the body 1 of theroof side rail portion RR by means of the mounting bolts 58 whileholding the inflator body portion 37 with the holding portion 57 a.

Here will be described how to mount the airbag device M1 on the vehicleV. First of all, the airbag 11 is so folded into a bellows shape fromits flat and expanded state sequentially with folds C of crests andvalleys as to bring the side of the lower edge 11 b of the airbag 11toward the side of the upper edge 11 a, as indicated by double-dottedlines in FIG. 2. The airbag 11 is wrapped, after folded up, atpredetermined portions with not-shown unfolding preventing breakabletape. Moreover, the mounting brackets 33 are attached to the individualmounting portions 25. Moreover, the clamps 55 are made in advance tosheathe the two end portions 20 a and 20 b of the inlet side portion 20in the connection port portion 19.

Here, the inflator 36 is assembled in advance by mounting the diffuser45 on the body portion 37.

Thereafter, as described hereinbefore, the diffuser 45 is inserted, withthe gas outlet ports 49 and 50 facing downward, from the side of therear end portion 20 c into the inlet side portion 20 in the connectionport portion 19 of the airbag 11. Moreover, the clamps 55 and 55 arefastened to force the front and rear end portions 20 a and 20 c of theinlet side portion 20 to contact with the outer circumferences of thefront and rear ends 45 a and 45 b of the diffuser 45. As a result, theinflator 36 is connected to the connection port portion 19 thereby toform the airbag assembly.

At this time, the gas outlet ports 49 and 50 of the diffuser 45 areopposed to the communication port 21 a of the connection port portion 19and directed toward the side of the feed passage portion 15 of theinflation portion 14.

Here, the mounting bracket 57 may be attached to the inflator bodyportion 37 either in advance or after the diffuser 45 was assembled.

After this, the individual mounting brackets 33 and 57 are arranged atpredetermined positions of the inner panel 2, and the airbag assembly isattached to the body 1 by means of the bolts 34 and 58. Next, theconnector 52 having the lead wires 53 extended from a predeterminedinflator activating control device is joined to the leading end face ofthe inflator body portion 37. Then, the pillar garnishes 4, 6 and 7 andthe roof head lining 5 are attached to the body 1 so that the airbagdevice M1 can be mounted on the vehicle V.

If the inflator 36 is activated after the airbag device M1 is mounted onthe vehicle V, the inflating gas G is discharged from the gas dischargeports 42 of the body portion 37 of the inflator 36. The inflating gas Gis released through the clearance between the outer circumference of thebody portion 37 and the inner circumference of the diffuser 45 and flowsfrom the gas outlet ports 49 and 50 of the diffuser 45 into the singleconnection port portion 19 of the airbag 11, as indicated bydouble-dotted lines in FIGS. 2 and 3. Moreover, the inflating gas Gflows from the communication port 21 a of the connection port portion 19into the inflation portion 14 of the airbag 11. Then, the airbag 11 isexpanded downward from the upper edge side of the windows W by inflatingthe inflation portion 14.

In the head protecting airbag device M1 of the first embodiment, theinflating gas G from the inflator 36 is fed to the inside of the airbag11 through the single connection port portion 19. In the airbag deviceM1, specifically, the inflator is connected to the single connectionport portion 19, not like the prior art in which the two ends of theinflator are connected to two connecting ports. In the airbag device M1of the first embodiment, therefore, it is easy to connect the inflator36 and the connection port portion 19.

In the airbag device M1 of the first embodiment, on the other hand, thegas outlet ports 49 and 50 of the inflator 36 are opposed to thecommunication port 21 a at the lower end of the connection port portion19 and arranged toward the side of the feed passage portion 15 of theinflation portion 14. The gas outlet ports 49 and 50 are opened on theouter circumference of the diffuser 45 and are axially directedgenerally perpendicular to the axial direction of the body portion 37 ofthe inflator 36 and the diffuser 45 of the inflator 36. Therefore, thecommunication port 21 a in the outlet side portion 21 of the connectionport portion 19 is axially directed like the gas outlet ports 49 and 50generally perpendicular to the axial direction of the inflator 36. Inshort, the inlet side portion 20 of the connection port portion 19having the inflator 36 inserted thereinto is arranged in the vehicle Vgenerally perpendicular to the axial direction of the communication port21 a, that is, bent generally perpendicular to the outlet side portion21.

With this construction, the inflating gas G from the inflator 36 isinjected downward or in the direction generally perpendicular to theaxial direction of the body portion 37 or the diffuser 45 of theinflator 36 so that it flows into the outlet side portion 21 and furtherinto the inflation portion 14 of the airbag 11. Therefore, the outletside portion 21 is held firmly by the inflator 36 even if downwardpressure is applied to try to separate the outlet side portion 21 fromthe inflator 36 by the injection force of the inflating gas G.Specifically, the inner circumference of the inlet side portion 20,especially, the upper side inner circumference 20 e on the side apartfrom the communication port 21 a is held firmly by the upper side outercircumference 45 c of the outer circumference of the diffuser 45 of theinflator 36 positioned opposite from the communication port 21 a, sothat the outlet side portion 21 is prevented from separating from theinflator 36. As a result, even if the connection structure between theinflator 36 and the inlet side portion 20 of the connection port portion19 is simplified to weaken the clamping force of the clamps 55 and 55,i.e., the connection strength, the inflator 36 itself holds theconnection port portion 19 firmly with the portion 45 c of its outercircumference, when the airbag device M1 acts, thereby to prevent theconnection port portion 19 from separating from the inflator 36.

In this airbag device M1, on the other hand, the assembly of thediffuser 45 with the body portion 37 of the inflator 36 is made by thesimple structure, in which the two ends 45 a and 45 b of the diffuser 45are pressed against the body portion 37. However, the inflating gas G isinjected downward generally perpendicular to the axis of the bodyportion 37 or the diffuser 45 from the gas outlet ports 49 and 50 of thediffuser 45. Even if the assembling force of the two ends 45 a and 45 bof the diffuser 45 to the body portion 37 is weak, therefore, thediffuser 45 is prevented from separating from the body portion 37. As aresult, the inflator 36 itself is assembled by simply connecting thediffuser 45 and the body portion 37.

Of course, the inflating gas G flowing into the inflation portion 14 ofthe airbag 11 flows toward the longitudinal middle of the inflationportion 14 through the connection port portion 19. Therefore, theinflating gas G promptly reaches the two longitudinal ends of theinflation portion 14 so that the airbag device M1 attains quickexpansion and inflation of the individual vertical cells 16 a in theinflation portion 14 of the airbag 11.

In the head protecting airbag device M1 of the first embodiment,therefore, the quick expansion and inflation of the airbag 11 isretained while simplifying the connection structure between the inflator36 and the airbag 11 and facilitating the assembly of the inflator 36itself. Therefore, the airbag device M1 can reduce the number ofworking-steps and the cost of assembly.

Moreover, the diffuser 45 and the inflator 36 are so assembled on thebody portion 37 as to force the root end of the diffuser onto a headportion of the body portion 37. In short, the diffuser 45 and the bodyportion 37 overlap each other. In the airbag device M1, therefore, theinflator 36 is compactly constructed without any axial elongation of theinflator 36.

In the first embodiment, moreover, the inflating gas G flows in the twooblique directions, i.e., forward and downward, and rearward anddownward, into the feed passage portion 15 of the inflation portion 14from the two gas inlet ports 49 and 50 of the diffuser 45 through thecommunication port 21 a of the outlet side portion 21. Therefore, theinflating gas G smoothly reaches the two longitudinal ends of theinflation portion 14 so that the airbag 11 attains an even quickerexpansion and inflation.

Especially in the case of the first embodiment, the inflating gas Gflows into the feed passage portion 15 which is arranged in thelongitudinal direction of the vehicle V on the side of the upper edge 11a of the airbag 11. Therefore, the vertical cells 16 on the front andrear ends of the inflation portion 14 can be easily inflated so that theairbag 11 achieves quick expansion and inflation.

In the first embodiment, moreover, inflation portion 14 of the airbag 11is so provided with the communication passage portion 17 as to extend inthe longitudinal direction of the vehicle V on the side of the loweredge 11 b of the airbag 11. Therefore, the inflating gas G easily flowsfrom the vertical cell 16 ab through the communication passage portion17 smoothly into the vertical cells 16 a at the front and rear ends ofthe inflation portion 14 thereby to promote the quicker expansion andinflation of the airbag 11.

In the first embodiment, on the other hand, the inlet side portion 20 ofthe connection port portion 19 of the airbag 11 is arranged along thelongitudinal direction of the vehicle V. In this construction, theinflator 36 is inserted into the inlet side portion 20. In the airbagdevice M1, therefore, the inflator 36 can be arranged in thelongitudinal direction of the vehicle V in parallel with the inflationportion 14 of the airbag 11. As a result, in the airbag device M1, theinflator 36 can be easily arranged in the thin roof side rail portion RRon the upper edge side of the windows W of the vehicle V.

In the first embodiment, moreover, the inlet side portion 20 of theairbag 11 is opened at its front and rear ends 20 a and 20 c and isprotruded from the upper portion of the outlet side portion 21 towardthe both front and rear directions. Moreover, the inlet side portion 20is sealed against the inflator 36 at two positions of the front and rearends 20 a and 20 c on either side of the outlet side portion 21 by thepressure on the outer circumference of the diffuser 45. In other words,the airbag 11 forms the connection port portion 19 into a T-shape havingthe outlet side portion 21 as its vertical rod and the inlet sideportion 20 as the horizontal rod. Moreover, the two sealed portions ofthe inlet side portion 20 are formed at the front and rear ends 20 a and20 c on either side of the outlet side portion 21. In the firstembodiment, therefore, the inflator 36 can be inserted from either thefront or rear end 20 a and 20 c of the inlet side portion 20 so that theflexibility in connecting the inflator 36 and the airbag 11 isincreased.

The embodiment is exemplified by the case in which the flange portion 46of the diffuser 45 is inserted from the side of the rear end 20 c of theinlet side portion 20 when the inflator 36 and the airbag 11 areconnected. In case the lead wires 53 are connected in advance with theinflator 36, however, the inflator 36 may be inserted into the inletside portion 20 by inserting the base portion 38 of the body portion 37from the side of the front end 20 a of the inlet side portion 20.

Here in the construction thus far described, the two sealed portions ofthe inlet side portion 20 on the inflator 36 are formed at the front andrear ends 20 a and 20 c on either side of the outlet side portion 21.However, those two sealed portions are individually formed by beingpressed on the circumferential direction on the outer circumference ofthe diffuser 45. Specifically, in the sealed portions, sealing pressureis secured in the circumferential direction of the diffuser 45 generallyperpendicular to the injection direction of the inflating gas G to beinjected downward from the gas outlet ports 49 and 50. Therefore, thosesealed portions retains sufficient sealing properties even if thepressure is not high. In the first embodiment, therefore, the individualsealed portions are enabled to retain the sufficient sealing propertieseven by the simple construction using the clamps 55 and 55 which arefixed by plastic deformation. In the first embodiment, therefore, thesealing structure is simplified to improve the connecting work of theinflator 36 and the connection port portion 19.

Here will be described a head protecting airbag device M2 of a secondembodiment, as shown in FIGS. 5 and 6. In this second embodiment, aninflator 66 is partially different from that of the first embodiment,and an airbag 11A is different from the airbag 11 of the firstembodiment. In this airbag device M2, moreover, there are used twomounting brackets 75 and 76 for mounting the inflator 66 on the vehicleV.

Here, the individual mounting brackets 75 and 76 include radiallyreducible cylindrical holding portions 75 a and 76 a, and mountingportions 75 b and 76 b having mounting holes 75 c and 76 c for insertingthe mounting bolts 58 thereinto. And, the mounting bracket 75 is mountedand fixed on the inner panel 2 by the bolt 58 while holding the outercircumference of the root portion 67 b of a body portion 67 with theholding portion 75 a. The mounting bracket 76 is mounted and fixed onthe inner panel 2 by the bolt 58 while holding the outer circumferenceof a leading end 70 a of a diffuser 70, which is sheathed by the inletside portion 20 of the connection port portion 19, with the holdingportion 76 a.

And, the airbag 11A is constructed like the airbag 11 excepting that theoutlet side portion of the connection port portion 19 in the airbag 11Ais slightly vertically longer than that of the airbag 11. Therefore, thedescription of the portions of the airbag 11A similar to those of theairbag 11 will be omitted, including the inlet side portion 20 of theconnection port portion 19 to insert the inflator 66 thereinto,designating them the same reference numerals as those of the airbag 11.

Moreover, the inflator 66 of the second embodiment includes the bodyportion 67 and the diffuser 70, as shown in FIGS. 5 and 6. The bodyportion 67 is formed into a cylinder type having gas discharge ports 68opened on its outer circumference for discharging the inflating gas G.The diffuser 70 is formed of a metal into a generally cylindrical shapeand is assembled with the body portion 67 while covering the gasdischarge ports 68, by being pressed on the outer circumference of thebody portion 67 at the two ends.

The generally cylindrical body portion 67 is of a stored gas type, whichis charged with a cold gas. The body portion 67 has a plurality of gasdischarge ports 68 in the outer circumference of the side of a front end67 a, and the connector 52 having the lead wires 53 connected thereto isjointed to the end face of the front end 67 a. The diffuser 70 isprovided on the side of its leading end (or front end) 70 a with aflange portion 71 protruded in the inner circumferential direction, andon the side of its root portion (or rear end) 70 b with curved portion72, which is curved toward the inner circumference to come into contactwith the entire outer circumference of the body portion 67. In the lowerportion toward the lower end 70 b of the diffuser 70, moreover, there isformed one gas outlet port 73, which is opened in a circular shape andis perpendicular to the axial direction of the body portion 67 of theinflator 66 and the diffuser 70. This gas outlet port 73 releases theinflating gas G downward. When mounted on the vehicle, the inflating gasG released from the gas outlet port 73 is guided into the feed passageportion 15 in the inflation portion 14 of the airbag 11A through thecommunication port 21 a of the outlet side portion 21 of the connectionport portion 19.

The diffuser 70 is assembled with the body portion 67 by arranging theO-ring 44 at the inner side face of the flange portion 71 and bysheathing the body portion 67 in the curved portion 72 at the rootportion 70 b from the front end 67 a. Then, the side of the flangeportion 71 is forced to contact with the outer circumference of theleading end 67 a while interposing the O-ring 44, and the curved portion72 is pressed against the outer circumference of the root portion 67 b.Thus, the front and rear ends 70 a and 70 b are connected to the outercircumference of the body portion 67 with good sealing properties. As aresult, the diffuser 70 is assembled with the body portion 67 and so theinflator 66 is assembled.

The inflator 66 thus assembled has its gas outlet port 73 directeddownward, and its rear end 66 b is inserted from the side of the frontend portion 20 a so that the diffuser 70 is inserted into the inlet sideportion 20 of the connection port portion 19 of the airbag 11A. Then,the front and rear end portions 20 a and 20 c of the inlet side portion20 are held by the clamps 55 to contact forcibly with the front and rearends 66 a and 66 b of the inflator 66, i.e., with the outercircumference near the front end 70 a of the diffuser 70 and near theroot portion 67 b of the body portion 67. Thus, the inflator 66 isconnected to the connection port portion 19.

At this connecting time, the airbag 11A is folded as in the firstembodiment, and has the mounting brackets 33 attached thereto. Moreover,the gas outlet port 73 of the diffuser 70 faces opposite thecommunication port 21 a of the connection port portion 19 above thecommunication port 21 a and thus is directed toward the feed passageportion 15 of the inflation portion 14.

After the inflator 66 is connected to the connection port portion 19,the airbag 11A and the inflator 66 are mounted and fixed on the vehicleV by using the mounting bolts 34 and 58, as in the first embodiment.Thus, the airbag device M2 is mounted on the vehicle V.

In this second embodiment, too, the inflating gas G is discharged fromthe gas discharge ports 68 of the body portion 67 of the inflator 66, ifthe inflator 66 is activated after mounted on the vehicle V. Theinflating gas G discharged is released from the gas outlet port 73 ofthe diffuser 70 through the clearance between the outer circumference ofthe body portion 67 and the inner circumference of the diffuser 70 intothe single connection port portion 19 of the airbag 11A, as indicated bytwo-dotted lines in FIGS. 5 and 6. Moreover, the inflating gas G flowsfrom the communication port 21 a of the connection port portion 19 intothe inflation portion 14 of the airbag 11A. Then, the airbag 11A admitsthe inflating gas G to inflate the inflation portion 14 so that it isexpanded downward from the upper edge sides of the windows.

In this head protecting airbag device M2 of the second embodiment, too,the inflating gas G from the inflator 66 is fed through the singleconnection port portion 19 into the airbag 11A. Specifically, in thisairbag device M2, too, the inflator 66 is connected to the singleconnection port portion 19, instead of the construction of the prior artin which the both ends of the inflator are connected to two connectionports, so that the inflator 66 and the connection port portion 19 areeasily connected to each other.

Moreover, the inflating gas G from the inflator 66 is injected downward,or in the direction perpendicular to the axial direction of the bodyportion 67 and the diffuser 70 of the inflator 66 into the outlet sideportion 21 and further into the inflation portion 14 of the airbag 11A.Therefore, the injection force of the inflating gas G tries to move theoutlet side portion 21 downward away from the inflator 66. However, theinner circumference of the inlet side portion 20, especially, the upperside inner circumference 20 e on the side apart from the communicationport 21 a, is held firmly by the upper side outer circumference 70 c ofthe diffuser 70 of the inflator 66 opposite from the communication port21 a. Therefore, the outlet side portion 21 is prevented from separaingfrom the inflator 66. As a result, the inflator 66 itself holds firmlythe connection port portion 19 by the portion 70 c of its outercircumference when the airbag device M2 acts, even if the connectionstructure between the inflator 66 and the inlet side portion 20 of theconnection port portion 19 is simplified to weaken the fastening forceof the clamps 55 and 55 and weaken the connection strength. Therefore,this airbag device M2 also prevents the connection port portion 19 fromseparating from the inflator 66.

In this airbag device M2, on the other hand, the assembly of thediffuser 70 with the body portion 67 in the inflator 66 is made by asimple structure in which the two ends 70 a and 70 b of the diffuser 70are pressed against the outer circumference of the body portion 67.However, the inflating gas G is injected downward, or in the directiongenerally perpendicular to the axis of the body portion 67 or thediffuser 70 from the gas outlet port 73 of the diffuser 70. Even if theassembling force of the two ends 70 a and 70 b of the diffuser 70 to thebody portion 67 is weak, therefore, the diffuser 70 is prevented fromseparating from the body portion 67. As a result, in this airbag deviceM2, too, assembly of the diffuser 70 and the body portion 67 is easilydone to form the inflator 66.

The inflating gas G flowing into the inflation portion 14 of the airbag11A naturally flows toward the longitudinal middle of the inflationportion 14 through the connection port portion 19. Therefore, theinflating gas G promptly reaches the two longitudinal ends of theinflation portion 14, so that the airbag 11A quickly expands andinflates the individual vertical cells 16 a in the inflation portion 14.

In the head protecting airbag device M2 of the second embodiment,therefore, the quick expansion and inflation of the airbag 11A issecured while simplifying the connection structure between the inflator66 and the airbag 11A and the assembly of the inflator 66. As a result,the airbag device M2 also reduces the number of steps and the cost ofassembly.

In the second embodiment, too, the diffuser 70 of the inflator 66 is somounted around the body portion 67 as to force the two ends 70 a and 70b to contact with the body portion 67. Therefore, the inflator 66 itselfis compactly constructed without elongating its axial length.

In the second embodiment, moreover, the gas discharge ports 68 of theinflator 66 are arranged toward the front end 67 a of the body portion67. However, the gas outlet port 73 is arranged close to the middle ofthe axial direction of the inflator 66, on the side away from the gasdischarge ports 68. With this construction, even the inflator 66 of thestored gas type can feed the inflating gas G smoothly into the airbag11A. In this inflator 66, specifically, the activating lead wires 53 areconnected to the end portion 67 a (or the front end 66 a of the inflator66), close to which the gas discharge ports 68 of the body portion 67are arranged. The side of the end portion 66 b of the inflator 66 whereno lead wire 53 is arranged, is inserted into the inlet side portion 20of the connection port portion 19 so that the end portion 66 a of theinflator 66, where the lead wires 53 are arranged, may be exposed fromthe opening 20 b of the inlet side portion 20 of the connection portportion 19. Thus, the gas outlet port 73 of the diffuser 70 is smoothlyopposed to the communication port 21 a.

In this second embodiment, too, the inlet side portion 20 of theconnection port portion 19 of the airbag 11A is arranged, like theairbag 11, in the longitudinal direction of the vehicle V. Therefore,the inflator 66 is easily arranged in the thin roof side rail portion onthe upper edge side of the windows of the vehicle V.

Still moreover, the inlet side portion 20 of the airbag 11A is opened atboth front and rear ends 20 a and 20 c, and is protruded to the frontand rear sides above the outlet side portion 21. Moreoever, the twosealed portions of the inlet side portion 20 on the inflator 66 areformed at the front and rear ends 20 a and 20 c on either side of theoutlet side portion 21, and are pressed on the outer circumference ofthe inflator 66 in the circumferential direction. Therefore, the inletside portion 20 of the inflator 66 can retain the sufficient sealingproperties by the simple construction using the clamps 55 and 55 fixedby plastic deformation. Moreover, the inflator 66 can be inserted fromeither side of the front and rear ends 20 a and 20 c of the inlet sideportion 20 thereby to increase the flexibility in connecting theinflator 66 and the airbag 11A.

In the second embodiment, still moreover, the front and rear sides ofthe inflator 66 on either side of the outlet side portion 21, that is,the outer circumference of the front end 70 a of the diffuser 70 and theouter circumference of the root portion 67 b of the body portion 67, aremounted on the inner panel 2 on the side of the body 1 by means of themounting brackets 75 and 76. Therefore, the inflator 66 itself is stablymounted on the inner panel 2. When the inflator 66 acts, moreover, theinjection force of the inflating gas G applies a pressure on the outletside portion 21 in the direction away from the inflator 66. However, theinflator 66 is inserted into the inlet side portion 20 which isprotruded to the front and rear sides of the inlet side portion 20 abovethe outlet side portion 21. Therefore, the inflator 66 itself cansuppress the movement of the inlet side portion 20 by the two endportions 20 a and 20 c of the inlet side portion 20 with the outlet sideportion 21 in between, thereby to support the connection port portion 19stably.

Here in the airbags 11 and 11A of the first and second embodiments, theconnection port portion 19 is formed into the T-shape, as viewed fromthe interior side, to open at the front and rear ends 20 a and 20 c ofthe inlet side portion 20 to be connected to the inflators 36 and 66. Asa connection port portion 79 of an airbag 11B of a third embodimentshown in FIGS. 7 and 8, however, an inlet side portion 80 may be bentinto an L-shape from an outlet side portion 81. Specifically, thisconnection port portion 79 is provided with the outlet side portion 81and the inlet side portion 80. The outlet side portion 81 has acommunication port 81 a opened in its lower end for communicating withthe feed passage portion 15 in the inflation portion 14 of the airbag11B. The inlet side portion 80 is bent from the upper side of the outletside portion 81 toward the front side of the vehicle V and is providedan opening 80 b in its front end 80 a. Here, the airbag 11B is differentin the construction of the connection port portion 79 and in theposition of the mounting portions 26, but the remaining constructionsare similar to those of the airbags 11 and 11A.

Moreover, an inflator 86 of this airbag device M3 of the thirdembodiment is provided with a diffuser 87 and the body portion 67identical to that of the second embodiment. The diffuser 87 is formed ofa sheet metal into a generally cylindrical shape and is assembled withthe body portion 67 to cover the gas discharge ports 68 of the bodyportion 67 and to have its two ends pressed on the outer circumferenceof the body portion 67.

The diffuser 87 is provided close to its leading end (or front end) 87 awith a flange portion 88 protruded in the inner circumferentialdirection and on the side of its root portion (or rear end) 87 b with acurved portion 89, which is curved toward the inner circumference sideand is forced into contact with the entire outer circumference of thebody portion 67. Below the vicinity of the side of the rear end 87 b ofthe diffuser 87 (or the rear end of the inflator 86), moreover, there isformed a generally semispherical bulge 90, which is protruded downward.This bulge 90 releases the inflating gas G downward or in the directiongenerally perpendicular to the axial direction of the body portion 67and the diffuser 87 of the inflator 86. The bulge 90 is provided withtwo gas outlet ports 91 and 92, each of which is opened in a circularshape for discharging the inflating gas G. When the airbag device ismounted on the vehicle, more specifically, the gas outlet port 91releases the inflating gas G obliquely, forward and downward to guidethe gas G, through the communication port 81 a of the outlet sideportion 81 of the connection port portion 79, to the front of the feedpassage portion 15 in the inflation portion 14 of the airbag 11B. In themeantime, the gas outlet port 92 releases the inflating gas G obliquely,rearward and downward to guide the gas G, through the communication port81 a of the outlet side portion 81 of the connection port portion 79, tothe rear of the feed passage portion 15 in the inflation portion 14 ofthe airbag 11B.

Moreover, this diffuser 87 is provided with two brackets 93 for mountingthe inflator 86 on the inner panel 2 by means of the bolts 58. Each ofthese brackets 93 is provided with a mounting hole 93 a for insertingthe bolt 58 thereinto.

The inflator 86 is assembled by arranging the O-ring 44 in the innerside face of the flange portion 88 and by mounting the curved portion 89of the side of the root portion 87 b from the side of the front end 67 aof the body portion 67. The flange portion 88 is put in contact with theouter circumference of the leading end 67 a interposing the O-ring 44,and the curved portion 89 is pressed against the outer circumference ofthe root portion 67 b. Thus, both front and rear ends 87 a and 87 b areconnected with the outer circumference of the body portion 67 with goodsealing properties. As a result, the inflator 86 is assembled.

For connecting the assembled inflator 86 to the connection port portion79, moreover, the root portion 87 b of the diffuser 87 is inserted, withthe gas outlet ports 91 and 92 directed downward, from the opening 80 bof the front end 80 a into the inlet side portion 80 in the connectionport portion 79 of the airbag 11B. Moreover, the vicinity of the frontend portion 80 a of the inlet side portion 80 is forced, while beingheld by the clamps 55, to contact with the vicinity of the longitudinalcenter of the inflator 86, or the vicinity of the middle of the diffuser87 and the flange 88. Thus, the inflator 86 and the connection portportion 79 are connected.

At this connecting time, the airbag 11B is folded as in the firstembodiment, and has the mounting brackets 33 attached thereto. Moreover,the gas outlet ports 91 and 92 of the diffuser 87 face toward thecommunication port 81 a of the connection port portion 79 above thecommunication port 81 a and are arranged toward the feed passage portion15 of the inflation portion 14.

After the inflator 86 is connected to the connection port portion 79,the airbag 11B and the inflator 86 are mounted and fixed on the vehicleV by using the mounting bolts 34 and 58, as in the first embodiment.Thus, the airbag device M3 can be mounted on the vehicle V.

In this third embodiment, when the inflator 86 acts, the inflating gas Gis discharged from the gas discharge ports 68. And, the gas G isinjected from the gas outlet ports 91 and 92 of the diffuser 87 throughthe clearance between the outer circumference of the body portion 67 andthe inner circumference of the diffuser 87 and flows through the singleconnection port portion 79 near the longitudinal middle of the airbag11B to the front side and the rear side in the feed passage portion 15of the inflation portion 14 in the airbag 11B. Even if the outlet sideportion 81 tries to leave the inflator 86, the upper side innercircumference 80 c of the inlet side portion 80 is held firmly by theupper side outer circumference 87 c of the diffuser 87 of the inflator86, thereby to suppress the movement of the outlet side portion 81.Therefore, the third embodiment achieves the same working-effects asthose of the first embodiment, excepting that the inlet side portion 80of the connection port portion 79 in the airbag 11B is not provided withboth front and rear openings on either side of the outlet side portion81.

In this third embodiment, the sealed portions on the outer circumferenceof the inflator 86 on the side of the end portion 80 a of the inlet sideportion 80 are forced to contact in the circumferential direction withthe outer circumference of the diffuser 87. Moreover, the sealed portionof the diffuser 87 is spaced by a clearance S from the outercircumference of the body portion 67. Even if the clamp 55 is fastenedwith more sealing pressure for sealing the inlet side portion 80 on thediffuser 87 than a predetermined level, therefore, the diffuser 87 iswarped to narrow the clearance S in between the body portion 67. As aresult, the sealing pressure need not be strictly set, which facilitatesthe connecting work of the connection port portion 79 and the diffuser87.

Here, in the second embodiment, as shown in FIG. 6, the clearance S alsois formed between the outer circumference of the body portion 67 and theinner circumference of the diffuser 70 at the connection portion by theclamps 55 between the diffuser 70 and the vicinity of the front end 20 aof the inlet side portion 20 of the connection port portion 19.Therefore, the aforementioned working-effects are also attained in thesecond embodiment.

In the third embodiment, moreover, the connection port portion 79 of theairbag 11B is formed into an L-shape, as viewed from the interior side,and is provided with the outlet side portion 81 extending upward fromthe inflation portion 14 and the inlet side portion 80, bent to thefront from the upper side of the outlet side portion 81. However, theconnection port portion 79 itself need not be formed into the L-shape,as long as it is formed, together with the airbag 11B, of a flexiblewoven fabric. For example, the connection port portion may be projectedeither straight upward from the side of the upper edge 11 a of theairbag 11B or obliquely forward or rearward while communicating with theinflation portion 14. When mounted on the vehicle, then, the connectionport portion thus formed may be bent in the L-shape to provide the sideof the inflation portion 14 of the connection port portion as the outletside portion, and the side connected to the inflator in which theinflator is inserted as the inlet side portion.

In the third embodiment, moreover, the connection port portion 79 of theairbag 11B is formed into the L-shape, as viewed from the interiorcompartment, and the inflator 86 is mounted and fixed at its front endside by means of the brackets 93 and 93. As in a fourth embodiment shownin FIGS. 9 and 10, however, an inflator 96 may be mounted and fixed onthe inner panel 2 on the side of the body 1 at the both front and rearends of the connection port portion 79 on either side of the outlet sideportion 81, even if this connection port 79 has an L-shape, as viewedfrom the interior compartment.

In this fourth embodiment, an airbag 11C is closed on the side of therear end 80 d apart from the opening 80 b in the inlet side portion 80of the connection port portion 79 and protrudes to the rear end 80 d tothe rear side of the outlet side portion 81. In this point, the airbag11C differs from the connection port portion 79 of the airbag 11B of thethird embodiment, but the remaining constructions are similar to thoseof the airbag 11B of the third embodiment.

And, the inflator 96 is provided with a diffuser 97 and the body portion67 identical to that of the second and third embodiments. The diffuser97 is formed of a sheet metal into a generally cylindrical shape tocover the gas discharge ports 68 of the body portion 67, and isassembled with the body portion 67 by having its two ends forced intocontact with the outer circumference of the body portion 67.

The diffuser 97 is provided, on the side of its leading end (or frontend) 97 a, with a flange portion 98 protruded to the inner circumferenceand, on the side of its root portion (or rear end) 97 b, with a curvedportion 99, which is so curved toward the inner circumference as toclosely contact with the entire outer circumference of the body portion67. Below the vicinity of the longitudinal middle portion of thediffuser 97, moreover, there is formed a bulge 100 which is protrudeddownward in a frusto-conical shape. In the slope of the bulge 100, thereare formed two gas outlet ports 101 and 102 opened in circular shapes.These gas inlet ports 101 and 102 release the inflating gas Gindividually downward or in the direction generally perpendicular to theaxial direction of the body portion 67 and the diffuser 97 of theinflator 96. When the airbag device is mounted on the vehicle,specifically, the gas outlet port 101 releases the inflating gas Gobliquely, forward and downward. Thus, the released gas G is guidedthrough the communication port 81 a of the outlet side portion 81 of theconnection port portion 79 to the front side of the feed passage portion15 in the inflation portion 14 of the airbag 11C. The gas outlet port102 releases the inflating gas G obliquely, rearward and downward. Thereleased gas G is guided through the communication port 81 a of theoutlet side portion 81 of the connection port portion 79 to the rearside of the feed passage portion 15 in the inflation portion 14 of theairbag 11C.

The diffuser 97 is assembled with the body portion 67 by arranging theO-ring 44 in the inner side face of the flange portion 98 and bymounting the curved portion 99 of the side of the root portion 97 b overthe body portion 67 from the side of the front end 67 a. And, the flangeportion 98 is forced to contact with the outer circumference of theleading end 67 a while interposing the O-ring 44, and the curved portion99 is pressed against the outer circumference of the root portion 67 b.Thus, the diffuser 97 is assembled with the body portion 67 while thefront and rear ends 97 a and 97 b are finely sealed with the outercircumference of the body portion 67. As a result, the inflator 96 isassembled.

For connecting the assembled inflator 96 to the connection port portion79, the root portion 97 b of the diffuser 97 is inserted, while the gasoutlet ports 101 and 102 being directed downward, from the opening 80 bof the front end 80 a into the inlet side portion 80 in the connectionport portion 79 of the airbag 11C. Then, the vicinity of the front endportion 80 a and the vicinity of the rear end portion 80 d of the inletside portion 80 are forced, while being held by the holding portions 76a of the mounting brackets 76, into contact with the front and rear endsof the inflator 96, i.e., the front and rear ends 97 a and 97 b of thediffuser 97. Thus, the inflator 96 is connected to the connection portportion 79.

At this connecting time, the airbag 11C is folded as in the firstembodiment, and has the mounting brackets 33 attached thereto. Moreover,the gas outlet ports 101 and 102 of the diffuser 97 face toward thecommunication port 81 a of the connection port portion 79 above thecommunication port 81 a and are arranged to face toward the feed passageportion 15 of the inflation portion 14.

After the inflator 96 is connected to the connection port portion 79,the airbag 11C and the inflator 96 are mounted and fixed on the vehicleV by using the mounting bolts 34 and 58, as in the first embodiment.Then, the airbag device M4 is mounted on the vehicle V.

In this fourth embodiment, when the inflator 96 acts, the inflating gasG is discharged from the gas discharge ports 68. Then, the gas G isinjected from the gas outlet ports 101 and 102 of the diffuser 97through the clearance between the outer circumference of the bodyportion 67 and the inner circumference of the diffuser 97. Subsequently,the gas G flows through the single connection port portion 79 near thelongitudinal middle of the airbag 11C to the front and the rear of thefeed passage portion 15 of the inflation portion 14 in the airbag 11C.Even if pressure is applied to the outlet side portion 81 in thedirection away from the inflator 96, the upper side inner circumference80 c of the inlet side portion 80 is held firmly by the upper side outercircumference 97 c of the diffuser 97 in the inflator 96, thereby tosuppress the movement of the outlet side portion 81. Therefore, thefourth embodiment achieves the same working-effects as those of thefirst embodiment, although the inlet side portion 80 of the connectionport portion 79 in the airbag 11C is not provided with the two openingson the front and rear on either side of the outlet side portion 81.Moreover, the inflator 96 can be stably mounted and fixed on the vehicleV.

Here, the gas outlet port to be formed in the diffuser of the inflatormay enter into the side of the outlet side portion 21 in the connectionport portion 19 of the airbag 11A, as shown in FIG. 11. This inflator106 is constructed to include a body portion 107 and a diffuser 113. Thebody portion 107 is formed into a cylinder type having gas dischargeports 111 open on the outer circumference for discharging the inflatinggas G. The diffuser 113 is formed of a metal into a generallycylindrical shape which extends over the gas discharge ports 111 of thebody portion 107 and is connected with the body portion 107 by pressingits two ends on the outer circumference of the body portion 107.

The body portion 107 is of a stored gas type, charged with a cold gas,and is provided with a base portion 108 and a head portion 109. The baseportion 108 is formed into a generally cylindrical shape and is arrangedon the side of the rear end 107 b of the body portion 107. The headportion 109 is formed into a generally cylindrical shape having aslightly smaller diameter than the base portion 108 and is arranged onthe side of the front end (or leading end) 107 a of the body portion107. The gas discharge ports 111 are arranged in the outer circumferenceclose to the leading end 109 a of the head portion 109, and theconnector 52 for inputting action signals from the action circuit of anairbag device M5 is connected to the leading end face of the headportion 109. Close to the root portion 109 b of the head portion 109,moreover, there is arranged a groove 110, which extends in the entirecircumferential direction, for mounting the diffuser 113.

The diffuser 113 is formed of a sheet metal into a generally cylindricalshape and is provided, on the side of its leading end (or front end) 113a, with a flange portion 114 protruded to the inner circumference and,on the side of its root portion (or rear end) 113 b, with a caulkingportion 115 to be fitted in the groove 110 of the body portion 107. Onthe front side of the caulking portion 115, there is formed acylindrical portion 116 with a bottom wall, which is protruded downward.The bottom wall 116 a of the cylindrical portion 116 is formed into aconical shape and is provided with two gas outlet ports 117 and 118,which are opened in circular shapes. These gas outlet ports 117 and 118release the inflating gas G downward or in the direction substantiallyperpendicular to the axial direction of the body portion 107 and thediffuser 113 of the inflator 106. When the airbag device is mounted onthe vehicle, specifically, the gas outlet port 117 releases theinflating gas G obliquely, forward and downward. The released gas G isguided through the communication port 21 a of the outlet side portion 21of the connection port portion 19 to the front of the feed passageportion 15 in the inflation portion 14 of the airbag 11A. The gas outletport 118 releases the inflating gas G obliquely, rearward and downward.The released gas G is guided through the communication port 21 a of theoutlet side portion 21 of the connection port portion 19 to the rear ofthe feed passage portion 15 in the inflation portion 14 of the airbag11A.

This diffuser 113 is connected with the body portion 107 by arrangingthe O-ring 44 on the inner face of the flange portion 114 and bymounting the diffuser on the head portion 109 of the body portion 107from the side of the diffuser root portion 113 b. And, the flangeportion 114 is applied to the outer circumference of the leading end ofthe head portion 109 while interposing the O-ring 44, and the caulkingportion 115 is fitted in the groove 110. Then, the diffuser 113 ismounted on the body portion 107 while the front and rear ends 113 a and113 b are finely sealed against the head portion 109 of the body portion107. As a result, the inflator 106 is assembled.

This inflator 106 is connected to the connection port portion 19 bymeans of the clamps 55 and 55, as in the first embodiment, and ismounted and fixed on the vehicle V by means of the mounting brackets 57.

The airbag device M5 using this inflator 106 achieves the sameworking-effects as those of the first embodiment. In the airbag deviceM5, moreover, the gas outlet ports 117 and 118 are entered into theoutlet side portion 21 of the connection port 19 and thus toward theinflation portion 14 of the airbag 11A. Therefore, the inflating gas Gcoming from the gas outlet ports 117 and 118 smoothly flows through thecommunication port 21 a of the outlet side portion 21 in two obliquedirections, i.e., forward and downward, and rearward and downward, intothe feed passage portion 15 of the inflation portion 14. Thus, the gas Gquickly reaches the two longitudinal ends of the inflation portion 14 sothat the quick expansion and inflation of the airbag 11A is secured inthe airbag device M5.

If the aforementioned point is not considered important, one gas outletport for releasing the inflating gas G downward may be arranged in thebottomed cylindrical portion 116 which is protruded below the diffuser113.

On the other hand, the inflators 36, 66, 86, 96 and 106 of the foregoingembodiments have been exemplified by the stored type, which are chargedwith a cold gas. However, the invention may use an inflator of thehybrid type or the like using reactive (or combustion) gas by chemicalreactions.

Moreover, in the connection port portion of each airbag or in thevicinity of the communication port in the feed passage portion, theremay be arranged, in addition to the diffuser, a flexible commutatingcloth, which releases the inflating gas to the front and rear of theairbag, or to the three sides, i.e., to the front, rear and lower sidesof the airbag.

1. A head protecting airbag device comprising: an airbag folded andhoused in the upper longitudinal edge of the window on the interior sideof a vehicle and adapted to expand and inflate downward, when it admitsan inflating gas, to cover the interior side of said window; and aninflator for feeding said airbag with the inflating gas, wherein saidairbag includes: an inflation portion to inflate, when it admits theinflating gas, to separate an interior side wall portion and an exteriorside wall portion of the airbag, thereby to shield said window; and onetubular connection port portion arranged close to the longitudinalmiddle of an upper edge side of said airbag and formed to communicatewith said inflation portion and to protrude upward from said inflationportion, for guiding the inflating gas from said inflator to saidinflation portion, wherein said connection port portion includes: anoutlet side portion having a communication port at a lower end thereoffor communicating with said inflation portion and releasing theinflating gas to said inflation portion; and an inlet side portionarranged above said outlet side portion and connected to said inflatorfor admitting the inflating gas from said inflator, wherein saidinflator includes: a cylindrical body portion having a gas dischargeport opened on the outer circumference side for discharging theinflating gas; and a diffuser formed of a metal into a cylindrical shapeto extend over said gas discharge port of said body portion, wherein thediffuser is connected to a body portion of the inflator in a sealedmanner at each of two ends of the diffuser, and a gas outlet port isformed on an outer periphery of the diffuser, and the inflation gasdischarged from the discharge port is released from the outlet port, andwherein the diffuser of said inflator is: inserted into the inlet sideportion of the connection port portion of said airbag and connected tosaid connection port portion with good sealing properties; and arrangedso that said gas outlet port faces toward said communication port ofsaid connection port portion and thus toward said inflation portion, andwherein, in the connection port portion, said inlet side portion is bentwith respect to an upper side of said outlet side portion, at least whenmounted on the vehicle, to form an L-shape, such that the inlet sideportion is perpendicular to the outlet side portion.
 2. The headprotecting airbag device according to claim 1, wherein, in an innerspace of the diffuser is sealed from an exterior space, which is outsideof the airbag and the diffuser, and a clearance is defined in the innerspace of the diffuser between the outer circumference of said bodyportion and the diffuser.
 3. A head protecting airbag device comprising:an airbag folded and housed in an upper longitudinal edge of the windowon the interior side of a vehicle and adapted to expand and inflatedownward, when it admits an inflating gas, to cover the interior side ofsaid window; and an inflator for feeding said airbag with the inflatinggas, wherein said airbag includes: an inflation portion to inflate, whenit admits the inflating gas, to separate an interior side wall portionand an exterior side wall portion of the airbag, thereby to shield saidwindow; and one tubular connection port portion arranged close to thelongitudinal middle of an upper edge side of said airbag and formed tocommunicate with said inflation portion and to protrude upward from saidinflation portion, for guiding the inflating gas from said inflator tosaid inflation portion, wherein said connection port portion includes:an outlet side portion having a communication port at a lower endthereof for communicating with said inflation portion and releasing theinflating gas to said inflation portion; and an inlet side portionarranged above said outlet side portion and connected to said inflatorfor admitting the inflating gas from said inflator, wherein saidinflator includes: a cylindrical body portion having a gas dischargeport opened on the outer circumference side for discharging theinflating gas; and a diffuser formed of a metal into a cylindrical shapeto extend over said gas discharge port of said body portion, wherein thediffuser is connected in a sealed manner to a body portion of theinflator at each of two ends of the diffuser, and a gas outlet port isformed on an outer periphery of the diffuser, and the inflation gasdischarged from the discharge port is released from the outlet oil andwherein the diffuser of said inflator is: inserted into the inlet sideportion of the connection port portion of said airbag and connected tosaid connection port portion with good sealing properties; and arrangedso that said gas outlet port faces toward said communication port ofsaid connection port portion and thus toward said inflation portion, andattached to the vehicular body at each of front and rear sides of saidoutlet side portion.
 4. The head protecting airbag device according toclaim 3, wherein, in an inner space of the diffuser is sealed from anexterior space, which is outside of the airbag and the diffuser, and aclearance is defined in the inner space of the diffuser between theouter circumference of said body portion and the diffuser.